Classifications

• • C—CHEMISTRY; METALLURGY
  • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
  • C10L—FUELS NOT OTHERWISE PROVIDED FOR; NATURAL GAS; SYNTHETIC NATURAL GAS OBTAINED BY PROCESSES NOT COVERED BY SUBCLASSES C10G OR C10K; LIQUIFIED PETROLEUM GAS; USE OF ADDITIVES TO FUELS OR FIRES; FIRE-LIGHTERS
  • C10L1/00—Liquid carbonaceous fuels
  • C10L1/32—Liquid carbonaceous fuels consisting of coal-oil suspensions or aqueous emulsions or oil emulsions
  • C10L1/326—Coal-water suspensions

Definitions

• This invention relates to stabilised aqueous slurries of pulverised coal, more particularly to such slurries which are stabilised by means of specified agents, which are valuable aids towards achieving the optimum fuel utilisation of coal.
• coal gasification processes and the reduction of the coal to finely divided form in suspension in oil, methanol or water.
• Coal-in-water slurries offer a number of conceptual and practical advantages, notably low cost, ease of handling and low transportation costs as compared with dry pulverised coal, comparatively high burning efficiency and lower ash yield after combustion.
• the slurries are prepared by admixing the finely pulverised coal with water, usually in the presence of dispersing agents and suspension stabilisers.
• the role of the dispersing agent is to prevent ftocutation or coagulation of the coal particles during the mixing process, whilst the suspension stabiliser serves to prevent settling out of the dispersed particles on storage of the slurry.
• the suspension stabiliser serves to prevent settling out of the dispersed particles on storage of the slurry.
• coal-in-water slurries of high coal content can be prepared which nevertheless have viscosities low enough to avoid or minimise these problems.
• a combustible composition consisting of a stabilised suspension of pulverised coal in water, the composition comprising
• the dispersing agents used are thus block copolymer condensates of aliphatic alcohols or alkylphenols with propylene oxide and ethylene oxide respectively.
• the poly(oxyethylene) block occupies the terminal position in the poly(oxyalkylene) chain:
• the group R in formula (I) may be a linear or branched alkyl group containing from 8 to 30 carbon atoms, preferably 16 to 20 atoms, for example the mixed Clb/C18 alkyl groups derived from commercial stearyl alcohol.
• the group R may be a linear or branched chain alkylphenyl group in which the alkyl group contains from 6 to 12 carbon atoms, for example a hexyl, octyl, nonyl or dodecyl group.
• the value of x in formula (I) is 10 to 20, and the value of y is 10 to 150, for example 80 to 120.
• the dispersing agents are readily obtained by the successive reaction of the appropriate aliphat c alcohol or of nonylphenol successively with propylene oxide and with ethylene oxide.
• the proportion of dispersing agent used preferably lies in the range 0.5% to 1.5% of the dry weight of the coal in the composition ; there may be used either a single dispersing agent or a mixture of two or more agents as defined.
• the pulverised coal for incorporation in the compositions of the invention may be obtained by techniques already well known such as by the use of tumbling mills or ball mills with recirculation of the ground material until the desired particle size distribution is obtained.
• the particle size of the coal is not critical for the purposes of the invention, but the preferred grade is that in which at least 8 ⁇ % of the particles are of a size below 75 microns.
• coal content of the compositions may vary between 30 parts and 90 parts by weight out of a total composition weight of 100 parts ; more typically, it will lie in the range 50 parts to 80 parts by weight.
• compositions of the invention may also contain conventional suspending or anti-settling agents.
• compositions are conveniently prepared by the steps of
• the dispersing agent indicated was dissolved or dispersed in water to yield the stated concentration based on dry weight of coal, and to the solution or dispersion was added pulverised coal in the stated proportion; the mixture was then subjected to the action
• Dispersing agent Agent A (nonylphenol condensed successively with 15.5 molar proportions of propylene oxide and 33 molar proportions of ethylene oxide.
• Dispersing agent Agent A, as in Example 1.
• Dispersing agent Agent B (nonyl phenol condensed successively - with 16 molar proportions of propylene oxide and 120 molar porportions of ethylene oxide).
• Dispersing agents Agent A and B as in Examples 1 and 3.
• Coal sample a non-beneficiated coal having an ash content of 15 - 20% by weight and an inorganic sulphur content of 2 - 4% by weight. 80% of the particles were of a size below 75 microns.
• Agent C nonylphenol condensed successively with 7.4 molar proportions of propylene oxide and 28.0 moles of ethylene oxide.
• Agent D nonylphenol condensed successively with 7.6 molar proportions of propylene oxide and 45.5 moles of ethylene oxide).
• Coal sample a beneficiated coal; 80% of the particles were of a size below 75 microns.
• Dispersing agent Agent D, as in Example 5.
• Coal sample a non-beneficiated coal ; 75.8% of the particles were of a size below 75 microns.
• Agent E commercial stearyl alcohol condensed successively with the 15 molar proportions of propylene oxide and 100 molar proportions of ethylene oxide).
• Agent A as in Example 1 :
• Coal sample No. 3 as described above was used for this series of experiments.
• Agent F nonylphenol condensed successively with 13.5 molar proportions of propylene oxide and 30 molar proportions of ethylene oxide.
• Agent G oleyl alcohol condensed successively with 15 molar proportions of propylene oxide and 100 molar proportions of ethylene oxide.
• Agent I stearyl alcohol condensed with 100 molar proportions of ethylene oxide.
• Dispersions were made up using 1% (based on dry weight of coal) and viscosity was measured with a Brookfield viscometer at 0.5 rpm using a No.3 spindle.
• additives of general formula (I) in which R is a C 16 to C 20 alkyl group, x is 10 to 20 and y is 80 to 120 may be used to make compositions in which, using 0.5 to 1.5% by weight additive based on the weight of coal, there is present from 67.5 to 70.5% weight of coal.

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• Chemical & Material Sciences (AREA)
• Oil, Petroleum & Natural Gas (AREA)
• Engineering & Computer Science (AREA)
• Chemical Kinetics & Catalysis (AREA)
• General Chemical & Material Sciences (AREA)
• Organic Chemistry (AREA)
• Emulsifying, Dispersing, Foam-Producing Or Wetting Agents (AREA)

Applications Claiming Priority (2)

Publications (3)

Family

ID=10533784

Family Applications (1)

Country Status (2)

Cited By (3)

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• 1983
  • 1983-09-23 EP EP83305660A patent/EP0109740B1/fr not_active Expired
  • 1983-09-23 DE DE8383305660T patent/DE3375930D1/de not_active Expired

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